I had once actually tested similar ideas, but I immediately discarded it since the performance was not really good.

It looks like they achieved around 100M rays per second in fully dynamic scenes. Given that we can trace maybe a few times more than that in static scenes, it isn't too bad, but maybe it still is not worth it. I'd personally just use ray tracing with a tree data structure. The use of uniform grid and limitations on geometry is not very fascinating for practical usage (though it is an interesting research result!)...